Alexander



UNITED STATES.V

PATENT CARL HEINRICH ELOEENZ MLLER, on HAMBURG, GERMANY.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 317,171, dated May 5,1885.

Application filed June 14, 1884. (Xo model.) Patented in England October2, 1882, No. 4,676.

To all whom it may concern.-

Be it known that I, CARL HEINEIcII FLO- RENZ MLLER, a subject of theEmperor of Germany, and a resident of Hamburg, in the German Empire,have invented certain new and useful Improvements in IncandescentElectric Lamps, of which the following is a specication.

lVIy invention relates to improvements in electric lamps where the lightis produced by the incandescence of a carbon filament in a Vacuum; andthe `objects of my improvements are, first, to shape the carbon filamentin such a manner that around the axis of the lamp or bulb an equallighting-surface will be visible; and, second, to facilitate theconnection of the carbon lament with the glass bulb. I attaintheseobjects by the device illustrated in the accompanying drawings, inwhich- Figures l and 2 are side elevations of my improved electric lampfrom two different points of vieW,-situated at right angle to eachother. Fig. 3 is a top view.

Similar letters refer to similar parts throughout the several views.

The carbonV laments of incandescent lamps as used up to this day allowonly a single line or little-more to be visible when observed fromcertain points of View, as the ascending part of the bow obscures thedescending one, and vice versa. The diffusion of the light at suchpoints of view is proportionately smaller than at such point-s where thecomplete bow can be seen, as the quantity of the diffused lightdecreases with the decreasing lightingsurface.

It has been proposed to make the carbon filament inthe form of twospirals crossing each other, in order that the lament can eX- pand andcontract freely; but the spirals have been of a very compact form,consequently each spiral obstructs a considerable portion of the lightemitted by the other.

According to my invention the carbon filament a is shaped in such amanner as to form two open cylindrical or conical spirals crossing oneanother, which terminate in a bow,

c', common to both, the diameter of said bow being the same or nearlythe same as that of the spirals. The two spirals and the terminal boware made of a single Iilament bent in the manner shown, or of twofilaments united at one of their ends, and the free ends are connectedto the platinum wires b in any convenient manner. 4The conducting-wiresb are sealed into glass tubes c, which, at their upper extremities, arebent outward and pass 4through the side walls of the small protuberancec', formed 011 the bulb c at points diametrically opposite to eachother. The glass tubes c are connected together and braced by meansofthe glass bars d. The bulb is sealed at the-point f on the summit of thebulb in the usual way after a sufficient vacuum has been produced withinthe bulb. This arrangement of the point f causes the light of the lampsto be diused more equally from the incandescent carbon, as noprojection, 8vo., will interrupt the globe or otherwise shaped surfaceof the glass bulb.

-Having thus fully described my invention, what I desire to claim, andsecure by Letters Patent, isp 1. In an incandescent lamp, a carbon iila`ment in the shape of an open double spiral,

the windings of which extend `in an inclined horizontal direction andcross each other, so

that the lament presents an equal amount of lighting-surfaceon allsides, substantially as and for the purpose set forth.

2. In an incandescent electric lamp, a carbon lament, a, of the shape ofan open double spiral, the windings of which extend in an inclinedhorizontal direction and cross each other, terminating in a bow, a', thefilament 'thus formed presenting an `equal amount of lighting-surfacefrom all sides, substantially 4 as and for the purpose set forth.

3. The combination, in au incandescent electric lamp, of the bulb e,having the protuberance e', with the connecting-wires b, .incased in theglass tubes c, the outer ends of which pass through the walls ofthe bulbat Vpoints diametrically opposite to each other,

together with the bars d and the carbon fila-` ment a, substantially asand `for the purpose set forth.

4. The combination, in an incandescent electric lamp, of the bulb c,Vconnecting-wires .Iool

of of windings of which cross one another, termil 4 1 i hating in a bow,a', substantially as and for CARL HEIBRICH FLORE MULLER' 5 the purposeset forth. Witnesses:

In testimony that I claim the foregoing as ALEXANDER SPECHT, myinvention I have signed my name, in pres` DIEDRIOH PETERSEN.

